Cheap solution for remote controlling aircon via wifi/mobile; Airconet. Supports a wide range of models and brands. Developer is interested in adding home assistant support for it and can provide code/info if someone could be interested in programming this. Price for the unit is under 20 USD on the web. [http://www.airconet.net/]
Is this doable?
Yes, but it is cloud-based, which might not be what many people want for their Home Assistant setup. But for people who don’t mind it being cloud-based, it’s a cheap functioning solution.